ML20100P087
| ML20100P087 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 11/19/1984 |
| From: | Hufham J TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-84 NCR-2318, NCR-2917, NUDOCS 8412130626 | |
| Download: ML20100P087 (4) | |
Text
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TENNESSEE 5VA13_EYCAM7HORITY CHATTA OGk, ENNESS N1 400 Chestnut Street Tower II 84 NOV 27 P I : 3 2 November 19, 1984 BLRD-50-438/83-30 BLRD-50-439/83-26 U.S. Nuclear Regulatory Comission Region II Attn:
Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - DEFECTS IN PIPF CLAMPS BY ITY ORINNELL - BLRD-50-438/83-30, BLRD-50-439/83 FINAL REPORT The subject deficiency was initially mported to NRC-0IE Inspector Linda Watson on April 6,1983 in accordance with 10 CFR 50.55(e) as NCR 2318. This was followed by our interim report dated May 6,1983 Related NCR 2917 was later initiated and is now being mported on with NCR 2318. This was followed by our interim reports dated May 24,1983 and August 28, 1984. Enclosed is our final report. We consider 10 CFR Part 21 to be applicable to this deficiency.
If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSE VALLEY AUTHORITY
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p J. W. Hufham, Manager Licensing and Regulations Enclosure co (Enclosure):
Mr. Richard C. DeYoung, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Comission Washington, D.C.
20555 Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339
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ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 l
DEFECTS.Di PIPE CLAMPS BY ITT GRINNELL
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BLRD-50-438/83-30, BLRD-50-439/83-26 10 CFR 50.55(e) l NCRs 2318 AND 2917 FINAL REPORT l
Description of Deficiency TVA has encountered the following problems with pipe clamps furnished by ITT Grinnell (ITTG), Providence, Rhode Island.
1.
Four-inch pipe clamps for use with figure 211 size A sway struts, supplied per Bill Of Material Mark No. 3BWO336-500 (Grinnell Shop Order No. EBH-517), will not tighten sufficiently on the-pipe to provide _ firm two-point contact in order to maintain proper alignment between the load stud and clamping bolt. This problem was verified by the ITTG field representative and was documented on nonconformance report (NCR) 2318.
As part of the indicated resolution of nonconformance report (NCR) 2318, l
64 of the 75 affected clamps were returned to ITTG for mwork. When l
the reworked clamps were returned to TVA, the clamps still could not achieve firm two-point contact. A new NCR, 2917, was initiated documenting the subsequent problem and is referenced above.
The root cause of the nonconformance has been traced to a miscommuni-cation of allowable clamp installation and inspection tolerances. TVA used an installation procedure in accordance with ITTG erroneous i
instructions which did not allow the clamp ears on the single-bolt side of the clamp to contact each other. These instructions have now been superced ed.
2.
All sizes of pipe clamps for use with figure 306/307 mechanical shock suppressors (all sizes) were manufactured with an incorrect dimension from the load pin / bolt to end of clamp (ear) causing an interference with the " snubber." This condition was documented on quality control inspection report (QCIR) 1563 and NCR 1710 as a generic condition and included numerous other QCIRs relative to individual components. A dimensional change made to the snubber design by the Pacific Scientific Company was not incorporated into the clamp design by ITTG.
3 Many sizes of figure 40 riser clamps used in conjunction with pipe luss on horizontal runs of piping would not tighten sufficiently on the pipe to provide firm two-point contact in order to maintain proper orientation on the pipe. This failure to maintain orientation causes (1) the associated sway struts or snubber to exceed the 40 tolerance which result in binding and (2) the clamp to pipe lug gaps to be inconsistent due to irregularities in the clamp width (reference QCIR 13844 and NCR 1633). This problem is attributable to an ITTG design error.
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'4 Two 1/2-inch pipa clamps for use with figure 211 sizo A sw;y struts, cupplied pnr Bill of Material 3BWO336-504 (ITTG thop ordsr Nos. EBH-149, EBH-521, and EBH-531) were fabricated such that the clamp bolt head falls in the radius of the clamp. Other dimensions also do not meet fabrication drawings (reference QCIR 29835 and NCR 2252). This problem and the following problems (items 5 through 10) are attributable to ITIG manufacturing errors.
5.
A pipe clamp, item 6 of drawing 1KE-MPHG-0765, sheet 2, revision 1 (detail A) varies in thickness from 1.509-inch to 1.350-inch as measured across the ears of the clamp. As the drawing calls for a stock thickness of 1.500-inch the item is out of allowable tolerance (reference QCIR 28005 and NCR 2265).
6.
A 32-inch pipe clamp, item 1.c of drawing 1SM-MPHG-0295, revision 3, will not tighten down on the pipe. The resultant installed position leaves approximately a 1/2-inch gap between the clamp and the pipe at a point 900 to the clamp split line (reference QCIR 30588 and support modification request 13845).
7.
A 30-inch pipe clamp, item 1 of drawing 1SV-MPHG-0261, sheet 2, revision 1, will not tighten down sufficiently to obtain firm two-point contact with the pipe (reference QCIR 30589).
8.
A 22-inch pipe clamp, item 1 of drawing 2CF-MPHG-0044, sheet 2, revision 4, will not tighten down sufficiently to obtain firm two-point contact with the >ipe (refemnce QCIR 30905).
9 A 24-inch pipe clamp, item 1 on drawing 1KC-MPHG-0003, sheet 1, would not fit the pipe properly. The clamp was returned to the vendor (reference QCIR 4676 ).
10.
A 24-inch pipe clamp, item 1 of drawing 1KC-MPHG-0010, revision 4, would not fLt the pipe prcperly due to a twist in the clamp. The clamp was returned to the vendor (reference QCIR 4639).
Safety Implications Some of the affected pipe clamps are used on primary safety-related systems.
Should the clamps fail to perform their intended function, the integrity of the affected system could be degraded, thus, adversely affecting the safe operation of the plant.
Corrective Action 1.
ITTG has indicated that there is no problem with these clamp ears touching and in fact the ears can be brought into complete surface contact with each other to achieve the required tightness with the pipe (reference ITTG's letter dated August 29, 1984).- The 64 clamps that were returned to ITTG a second time were installed on 4-inch outside-diameter pipe by ITTG. They were inspected by TVA personnel and were found completely acceptable. TVA has asked ITTG to return the clamps to the site for TVA use.
In ord:r tol prevent recurrenes of this candition, TVA'c Offica of Construction (00) h2s cgreed to revica cita qu:lity control procedure (QCP) 6.17 to clarify. the allowable clamp installation and inspection tolerances. This procedure revision will be accomplished by December 14, 1984.
2.
TVA has mworked all the affected clamps in accordance with ITIG's instruc tions. QCP 6.17 has been revised to incorporate ITIG's inspection and nework procedures.
ITIG clamp manufacturing drawings were revised to cover all clamps manufactured after April 1980.
3 TVA has mworked all identified nonconforming clamps in accordance with QCP 6.17, and the ITTG procedures which are included in disposition of NCR 1633. Any remaining unidentified clamps will be worked on a case-by-case basis. As of April 26, 1983, ITIG designs all figure 40 riser clamps used with sway struts and snubbers such that the clamps will maintain firm two-point contact.
4.
The ASME code contains the NF minimum edge distance criteria; however, the lower bolt does not have a load towards the edge of the clamp.
Consequently, the dimensional discrepancy is acceptable. Also, although the bolt head is on the clamp bend radius, the structural integrity of the lower bolt is not impaired. Based on this evaluation ITIG concluded, in their letter dated April 4, 1983, that the clamps can be used as-is.
5.
ITIG verified by analysis that the clamp is acceptable "as is" for the design intended. This is documented by ITIG's letter to TVA dated May 11, 1983.
6, 7, and 8 TVA has reworked the clamps at the jobsite in accordance with site QCP 6.17, and ITIG procedure.
9 and 10 ITIG replaced the clamp with a new one on February 27, 1981.
In addition, ITIG notified its manufacturing and quality control personnel on June 1, 1983, of the specific problems identifled in items 5 through 10 above and cautioned them to be more careful in the future.
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